Electric switch mechanism



m z: I O V NTOR f5 Z BY O H A) a y 1941" c. J. HULL 2,248,674

ELECTRIC SWITCHYMECHANISM Filed 001:. 18. 1959 76 2 ATTORNEY Patented July 8, 1941 OFFICE ELECTRIC SWITCH MECHANISDI Application October 18, 1939, Serial No. 300,041

(Cl. 2(l033) 7 Claims.

lhis invention relates to electrical switches but more particularly to a switch whose contacts are held in conducting relation for a predetermined time and then broken without effort or care on the part of the operator.

An object of the invention is to provide a switch mechanism which requires but a single push of a button to make or break switch contacts, yet holds such contacts closed or open for a definite or predetermined period of time and then automatically opens or closes them depending upon the nature of the circuit of the switch mechanism control.

Another object of the invention is to provide a switch mechanism which is adaptable to various uses, which is simple and rugged in construction and reliable and efficient in operation and which is composed of a minimum number of parts.

Other features of the invention reside in the construction and arrangement of parts hereinafter described and particularly pointed out in the appended claims.

In the accompanying drawing:

Figure l is a side elevational View of the switch mechanism embodying my invention. Figure 2 is a similar view looking at the opposite side thereof. Figure 3 is an enlarged longitudinal section taken on line 3-3, Figure 7, showing the parts in their normal or inoperative position. Figure l is a similar view showing the parts in an operative or time-governed switch closing position. Figure 5 is a similar view showing the parts in a position immediately after the switch has been automatically opened or at the end of its operative, time-governed position. Figures 6 and 7 are vertical sections taken in the plane of the correspondingly numbered lines in Figure 1.

Similar characters of reference indicate corresponding parts throughout the several views.

It is desirable, in certain circuit set-ups, to cause the circuit to be closed at a switching point for a sufficient time to effect a certain result, as for example, to cause current to flow through the coil of an electro-magnet for a predetermined time to insure saturation of its core and overcome the inertia of its armature to effect the proper performance of the secondary function of the magnet. When such a switch is left completely to the control of the user, particularly by an unskilled person, the time element may not be sufficient to properly perform the functions required of a particular circuit. To obviate this condition and eliminate guess work on the part of the user, I have created a switch mechanism which requires but a push bu ton action on the part of the operator, while the time element or period of closure of the circuit is automatically controlled.

By way of example, my invention has been shown in connection with a switch unit including a supporting block or body it) having mounted on its top side spaced, parallel switch elements ll, l2 and an intervening movable switch element !3, which normally engages the companion lower switch element H, as shown in Figures 1, 2 and 3 to maintain a given circuit closed, and which is adapted to be projected into contact with the upper switch element i2, as shown in Figure 4-, to maintain the circuit thereof closed for a predetermined period of time. At its free end the movable switch element has an insulated actuating head At its lower side the body ID has an enlarged boss or guide hub E5 in which a manually-operated push rod or plunger I6 is slidingly mounted for initiating the movement of the switch element 53 upwardly into contact with the companion switch element i2. A coil spring ll applied to the push rod tends normally to urge it to its retracted or inoperative position shown in Figure 3, and in which position a stop pin is borne by the rod abuts against the adjoining edge of the body it to limit its retracted movement.

Actuated in response to the forward or operative stroke of the push rod it, for actuation in a combined longitudinal and vertical direction into a position to floring the movable switch element it intocontacting engagement with the companion element i2 and for subsequently maintaining such switch elements closed for a predetermined time, is a substantially L-shaped striker plate or switch-governing lever l9 having a iulcruming stud or pin 2% at its outer end ongaging a longitudinal guide-way or groove 2| formed in the face of the body it and relative to which such lever is adapted for longitudinal movement as well as a vertically-swinging move ment about its fulcruming axis. The inner or free offset end of this switch-governing lever has a laterally-bent lug 22 thereon which is normally disposed in the path of endwise travel of the push rod it for actuating such lever in the manner stated. At its top edge the lever i9 has a switch-engaging surface or dwell 23 which is adapted to contact the switch-head it and elevate it to close the switch-elements l2, l3 and maintain them closed, the length of such dwell surface being predetermined in accordance with the time element desired for a given switch-closing condition or operation. For the purpose of guiding the lever into its switch-closing and sustaming positions and subsequently effecting its return to initial position wherein the switch elements H and [3 are again closed, said lever has a follower pin or roller 24 extending from its inner face and adjacent the free end thereof which engages an endless cam-groove 25 formed in the opposing face of the body l and of substantially rectangular shape in plan, as clearly shown in Figure 3. A spring 26 connected at one end to the lever 19 and at its other end to the body it] serves to normally urge the lever to its normally retracted and downwardly-swung position shown in Figures 2 and 3, in which position the follower pin is lodged at the lower near corner of the cam-groove, while the fulcruming stud 20 is in abutting contact with the rear end of its companion guide-way 21 with the leverlug 22 adjoining the end of the push rod 56.

A cover plate 2! is preferably applied to the grooved face of the body it and over the switchgoverning lever i9 and is notched at 28 to allow 101' the free movement of the lever-spring 26.

In operation, assuming the parts to be in the normal inoperative position shown in Figure 3, with the switch elements H and I3 closed, and it is desired to break such connection and close the companion switch elements i2 and 13 for a predetermined period of time, the operator presses the push rod I6 forwardly its maximum stroke and releases it immediately, whereupon the spring ll promptly returns it to its initial position. During its forward stroke, the push rod encounters the lug 22 of the switch-governing lever ii] and projects the latter forwardly in a horizontal plane against the resistance of the spring 226 until the follower pin 24 encounters the inclined. portion of the groove 25, at which time said lever is swung upwardly about its traversing pivot-stud 29, to bring its surfaces 23 into contact with the actuating head 14 of the movable switch element i3 to elevate the same into engagement with the companion element i2 and out of engagement with the normally-closed element ll, as shown clearly in Figure a, in which position the push rod is in its extreme advanced position. Upon the release of the push rod, it is promptly returned by its spring IT to its normal position, while the switch governing lever is restored independently to its position by the spring 26. During the restoring stroke of such lever, it is initially guided in a horizontal plane in the upper portion of the groove 25 to thereby retain the switch I2, 13 closed for a period of time determined by the length of the lever-surface 23, after which the lever is urged downwardly by the spring 26 with its follower pin 24 engaging the upright portion of said groove and with the result that the switchhead [4 rides oif the lever to automatically open the switch elements l2, l3 and again close the switch elements H, 13.

t will be seen that no matter how rapidly or slowly the push rod i6 is depressed by the operator, it does not in any way alter the length of time the switch contacts are held closed and opened. If the operator holds the push rod in for an abnormal period at the end of its forward stroke, the rod-engaging lug 22 on the switchgoverning lever l9 rides oil the end of the push rod, as shown in Figure 4, and engages the top side of such rod until the latter is released.

I claim as my invention:

1. In a switch mechanism of the character described, a support having guide means thereon, a pair of companion switch elements mounted on said support, one of which is movable relatively to the other to and for a switch-closing position, a member slidably engageable with said guide means and projectable to and from operative engagement with said movable switch element for sustained engagement therewith during its cycle of movement to maintain the switch elements closed over a predetermined time period, and means engageable with said member for initiating its movement to a projected switchclosing position.

2. In a switch mechanism of the character described, a pair of companion switch elements, one of which is movable relatively to the other L0 and from a switch-closing position, a member movable longitudinally relatively to said switch elements and projectable to and. from operative engagement with said movable switch element 101 governing its closing and opening movements, means connected to said member for normally urging it to a switch-opening position, and means engageable with said switch-governing member for guiding it longitudinally in sustained engagement with the movable switch element for a predetermined time during the movement of sucn member to switch-opening position.

In a switch mechanism of the character described, a pair of companion switch elements, one of which is movable relatively to the other to and from a switch-closing position, a member movable longitudinally relatively to said switch elements and projectable to and from operative engagement with said movable switch element for governing its closing and opening movements, means connected to said member for normally urging it to a switch-opening position, means engageable with said switch-governing member for guiding it longitudinally in sustained engagement with the movable switch element for a predetermined time during the movement of such member to switch-opening position, and a normally-retracted push rod for projecting said switch-governing member toward switch-closing position.

4. In a switch mechanism of the character described, a pair of companion switch elements, one of which is movable relatively to the other to and from a switch-closing position, a combined vertically-swinging and horizontally displaceable member operatively engageable with said movable switch element for governing its opening and closing movements, a spring connected to said member for normally urging it vertically and horizontally to a switch-opening position, and means engageable with said switch-governing member for guiding it in its vertical and horizontal paths of displacement.

5. In a switch mechanism of the character described, a pair of companion switch elements, one of which is movable relatively to the other to and from a switch-closing position, a combined vertically-swinging and horizontally displaceable member operatively engageable with said movable switch elements for governing its opening and closing movements, a spring connected to said member for normally urging it vertically and horizontally to a switch-opening position, and means engageable with said switchgoverning member for guiding it in its vertical and horizontal paths of displacement, said guide means including a portion for maintaining said member in sustained engagement with the movable switch element during the horizontal displacement of such member in a direction to open the switch.

6. In a switch mechanism of the character described, a pair of companion switch elements, one of which is movable relatively to the other to and from a switch-closing position, a combined vertically-swinging and horizontally displaceable member operatively engageable with said movable switch element for governing its opening and closing movements, said member having a horizontally-extended contact face for engagement with the movable switch element for predetermining the duration of closing of the switch, a spring connected to said member for normally urging it vertically and horizontally to a switchopening position, and means engageable with said switch-governing member for guiding it in its vertical and horizontal paths of displacement.

'7. In a switch mechanism, a body having a pair of companion switch elements thereon, one of said elements being movable relatively to the other to and from a switch-closing position, said body having a longitudinal groove and an endless groove therein, a vertically-swinging and horizontally-displaceable switch-governing lever mounted on the body and having a pivot guided in said longitudinal groove and a follower pin engaging said endless groove, the upper surface of said lever being adapted for engagement with said movable switch element and being of a length to predetermine the duration of closing of the switch, a spring applied to said lever for normally urging it to a retracted switch-opening position, and a push rod engageable with said lever for actuating it to its initial switch-closing position.

CHARLES J. HULL. 

